The present invention relates to a valve deactivation system for use with internal combustion engines.
Generally, cylinder deactivation is the deactivation of the intake and/or exhaust valves of a cylinder or cylinders in an internal combustion engine during at least a portion of the combustion process. Deactivating one or more cylinders reduces pumping work and is a proven method by which fuel economy can be improved. In effect, cylinder deactivation reduces the number of engine cylinders within which the combustion process is taking place. With fewer cylinders performing combustion, fuel efficiency is increased. Cylinder deactivation is particularly effective during part-load conditions when full engine power is not required for smooth and efficient engine operation. Studies have shown that cylinder deactivation can improve fuel economy by as much as fifteen percent.
Conventional devices used to achieve cylinder deactivation are typically moderately complex mechanical devices assembled from numerous subassemblies and component parts. The assembly of a device from numerous component parts requires significant labor and the need to inventory and maintain a supply of the various component parts, thereby increasing the cost of manufacture. Furthermore, the numerous component parts used in a conventional cylinder deactivation device contribute mass to the device, may impact the reliability of the device, and may limit the performance of the device to a limited range of engine operation.
The additional component parts, such as, for example, multiple springs, arms and shaft members used in a conventional cylinder/valve deactivation system have typically not fit within the space occupied by standard drive train components. Therefore, the conventional methods of implementing cylinder deactivation have required modification and redesign of valve trains and engines to provide the needed space within which to house the additional deactivation components. Furthermore, it has typically been necessary to custom design a unique cylinder/valve deactivation system for each particular model of engine. Thus, substantial amounts of research and development, engineering resources, and testing were required in order to develop a unique system for each type or model of engine.
Therefore, what is needed in the art is a cylinder deactivation device which is designed to more readily fit within existing space occupied by standard drive train components, thereby avoiding the need to redesign engines and their valve trains.
Furthermore, what is needed in the art is a cylinder deactivation device that is relatively simple and uses fewer component parts, and is therefore manufactured in a more cost-effective manner.
Even further, what is needed in the art is a cylinder deactivation device which can be used with a variety of valve train configurations, thereby reducing the need to design a unique valve/cylinder deactivation system for each engine model.
Moreover, what is needed in the art is a cylinder deactivation device which utilizes conventional valve train components as part of the deactivation system, and enables cylinder deactivation over a wide range of engine operation.
The present invention provides a valve deactivation system for use with an internal combustion engine.
The invention comprises, in one form thereof, a deactivation rocker arm assembly and a free motion spring assembly. The deactivation rocker arm assembly includes an elongate rocker arm defining an aperture. A center post is slidingly disposed within the aperture. The center post is configured for engaging a valve stem of a valve of an internal combustion engine. Coupling means selectively couple together and decouple the center post and the rocker arm The free motion spring assembly includes an inner spring retainer surrounding a portion of the valve stem. An outer spring retainer surrounds a portion of the valve stem. An inner spring surrounds a portion of the valve stem between the inner spring retainer and a disk cap associated with the valve stem. An outer spring surrounds the inner spring.
An advantage of the present invention is that it is more readily fits within existing space occupied by standard drive train components, and thereby avoids the need to redesign engines and/or engine valve trains.
Another advantage of the present invention is that it uses fewer component parts, and is therefore manufactured in a cost-effective manner.
Yet another advantage of the present invention is that it can be used with a variety of conventional valve train configurations, and thereby reduces the need to design a unique valve/cylinder deactivation system for each engine model.
A still further advantage of the present invention is the conventional valve spring of the internal combustion engine is utilized as a component of the valve deactivation system, thereby reducing the complexity of the system.